The present invention relates to human vision and alternatives for the blind in order to see using something other than the eyes. Visually impaired people have used devices for centuries to help them perceive the world. In these systems, the brain's plasticity performs a rewiring of the optical cortex in order to make this happen. It has been found that the blind person does not feel the forces in a cane handle but mentally translates this into a modified ‘feel’ of the surface of the ground on which the cane is sliding around.
Another example is the use of Braille which is a series of bumps ‘read’ by the blind as a form of written language. In skilled readers of Braille, the brain's plasticity alters perception such that several fingers move and sense like one large finger and the reading speed is quite fast.
More recently, other technical devices have become available. One such device is a cane that has a series of sonar devices that play a tone warning the user of imminent collisions.
New research is revealing the brain's plasticity to be quite adaptable. In a remarkable example developed by Bach-Y-Rita in a U.S. Federal government program, a video image was converted by a computer and played into a rectangular array of pins pressing out an image on a, person's back. In an alternate form, a dental retainer is used with an array of electrical stimulators which ‘shock’ the taste of an image onto a persons tongue. Although strange in its approach, this last technique has had some amazing successes.
Another promising direction in alternate mental inputs has been in the direct wiring of computers into the eye, the retina, the optic nerve, and into various parts of the brain. The obvious negative side of this approach is the required surgery involved in attaching to internal organs. One other negative risk relates to a test case where the misfiring of brain connectors resulted in research patients having seizures.
The plasticity of the mind is a powerful tool to achieve this. In a research project using Ferrets, (the small mammal), the optic nerve was cut on babies and rerouted to the portion of the brain normally used for auditory input. The Ferrets grew up with apparently, ‘normal’ vision. It is presumed that the brain is searching for signals providing spatial information and uses this to form mental images of the surroundings.
The brain of a baby Ferret (or a human) does not care whether the source of the nerve impulse patterns come as auditory, optical, or radar information as long as it provides the spatial reference needed to thrive. The brain is able to learn and translate impulses from the eyes as images and can translate other nerve impulses as well.
The crux of all this is that a tremendous amount of data is transferred to the human brain from sense organs we call ‘eyes’. Alternative input devices must somehow deal with high information density and the prior art either has low data density as in canes or has high cost as in invasive surgery.
Therefore, there is a need for a cost-effective, alternative to seeing for blind people that takes advantage of the human brain's plasticity.